Designing Kitchens and Bathrooms - Getting ready to tile shower wall...questions

1. Trowl size for 6 x 6 tile?
2. Hardibacker. Do I install with a 1/8 gap between sheets? If so, why?
3. Tar paper or 6 mil plastic? Attach it with a heavy duty stapler?
4. Do I tape and skim the corners with thinset?
5. Use the straight side of trowl to apply thinset?
6. When do I take the 1/8 spacers out?

I am concerned with taping the seams and skim coating. Won't build up the seam where it puts it off much will it?

I plan getting the hardi up. Setup a 1 x 2 around for a ledger, tile the first row. Leave it and start in new the next day.

Thanks.

1.) 1/4" x 1/4" should be fine unless the tile have deep hollows on the back, most dont.
2.) I do. I want thinset to fill the gap and work with the tape to unify the boards.
3.) Either or. Whatever you find easier to work with. Stapler is the way to go.
4.) Yes, very important to do. Also do the seams on the wall. Use the mesh tape and modified thinset. The white is creamier and flows better than the gray. I put it on with a 4" spackle blade then smooth it out with a 6" blade.
5.) It can leave a slight hump if you tape first but I go a little heavy with the thinset when setting the tile and that takes the problem away. You can tape as you go about setting the tile. Most recommend to do it that way. Use the notched side to spread the tinset.
6.) Wait until the next day or about 18-24 hours, depending on humidity.

You can stack additional rows up on the one that rests on the ledger board right away, no need to wait. Go about half way up and call it a day. If you do wait then go all the way.

A number of people (-Lowes, HD), including two tiles guys have suggested using Mastic on my bathroom walls for tile. That is incorrect eh? And why?

And, I have put up two hardibacker boards and there is a 5/8's inch gap in the corner where the two backer boards meet. Should I use tape and thinset to fill gap or cut a little slice of backer board and then fill and tape with thinset?

If what you are tiling is a tub surround or shower (a wet area) then yes the Lowes HD guys are wrong again for a change. Big box stores are never a source for good information. Use a modified thinset to set the tile. As to the why, mastic reimulsifies when it gets wet. Once thinset sets up water cant hurt it. Mastic should only be used on walls in non wet areas like a kitchen backsplash. Someplace where you dont have continious water exposure. Mastic shouldnt be used on large format tile, and never ever with natural stone. Mastic shouldnt be used on floors either.

5/8" is a big gap. Use alkalai resistent mesh tape and modified thinset to fill the gap. On a wall you should be ok with that.

I do have alkalai resistent mesh tape and modified thinset from Lowes. Walls were way out of plumb/square so I built them out and they are pretty steady. I actually just cut it a bit short...re the 5/8's. (Measure twice...)

My trowl says...1/4" x something x 1/4" , that is fine is it?

Thanks for the help.

If the trowel is 1/4" x 1/4" x 1/4" thats good for your size tile. If its 1/4" x 3/8" x 1/4" thats probably to big for 6" x 6" tile.

And...

What is an epoxy grout float? Are there other types of floats? I have one with rubber like stuff on the bottom.
I am using Spectralock grout.

(The more I read...the more I don't know).

Check this link - its toward the bottom.

http://www.tiletool.net/Grout_Floats.asp

Epoxy grout is not necessary for a shower. Regular sanded or non sanded grout works fine in a shower. Epoxy grout is expensive and a pia to work with as compared to regular grout.